The present invention relates to a method for detecting and localizing errors in redundant primary detectors of an automation system.
Until now, in redundant automation systems, only methods for detecting typical line defects occurring between primary detectors and the automation system (e.g., short-circuits or broken wires) were known. When such a defect was detected the signal from the detector with the defective line was ignored. Previously, no method existed for automatically detecting faults in the detectors themselves. Until now, if an installation was designed to be highly redundant or fault tolerant, the process to be controlled could still be incorrectly controlled if an undetected detector fault existed. This resulted in damages. Further, if the installation was designed to be highly reliable (i.e., fail safe), the installation could be shifted to a safety condition, such as a shut down condition, even when the technical process could have been controlled by another detector that was properly functioning. This resulted in production losses.
The present invention provides a solution to the shortcomings of the prior art. The present invention automatically detects not only line defects, but also detector errors and these errors can be localized with a high degree of probability.